| Type: | Family | Name: | Hyaluronidase PH20 |
| Description: | O-Glycosyl hydrolases () are a widespread group of enzymes that hydrolyse the glycosidic bond between two or more carbohydrates, or between a carbohydrate and a non-carbohydrate moiety. A classification system for glycosyl hydrolases, based on sequence similarity, has led to the definition of 85 different families [, ]. This classification is available on the CAZy (CArbohydrate-Active EnZymes) web site.Family 56 () encompasses a group of hyaluronidases () that includes venom hyaluronidases and mammalian sperm surface proteins (PH-20).PH-20 is required for sperm adhesion to the egg zona pellucida; it is located on both the sperm plasma membrane and acrosomal membrane []. During fertilisation, sperm must first penetrate a layer of cumulus cells that surrounds the egg, before reaching the zona pellucida. The cumulus cells are embedded in a matrix containing hyaluronic acid, which is formed prior to ovulation. PH-20 facilitates penetration of the cumulus cell layer by digesting hyaluronic acid []. The amino acid sequence of the mature protein contains approximately 460 amino acids, and includes six potential N-linked glycosylation sites and twelve cysteines,eight of which are tightly clustered near the C terminus []. | Short Name: | Hyaluronidase_PH20 |
